An optical instrument is an instrument used to move light along a specified path or paths. Microscopes are common, general-purpose optical instruments. Other optical instruments include interferometers and spectrophotometers. Microscopes are generally used to view objects that are too small to be seen by the unaided eye. Optical microscopes use visible light and a system of lenses to magnify images of small objects. High magnification optical microscopes are often heavy and take up much volume. There is a need for improved optical lenses for use in optical instruments.